Photocomposing machine

ABSTRACT

This invention relates to photographic type composing machines capable of automatically mixing a plurality of fonts, styles, or faces, and more particularly to machines presenting a selected character (from a given alphabet or font) at a common character presentation point from which its image is projected onto a light sensitive surface. The invention describes a method for rapidly changing from one character font to another solely by the utilization of either the character spacing mechanism of the machine, or the line spacing mechanism thereof.

United States Patent Moyroud I [54] PHOTOCOMPOSING MACHINE [72]Inventor: Louis M. Moyroud, c/o Photn lnc., 355 Middlesex Ave.,Wilmington,

Mass. 01887 [22] Filed: Nov. 12, 1970 [21] Appl. No.: 88,920

Related US. Application Data [63] Continuation-in-part of Ser. Nos.827,128, May 21, 1969, Pat. No. 3,643,559, and Ser. No. 690,720, Dec.13, 1967, Pat. No. 3,590,705, and Ser. No. 843,297, July 22, 1969, Pat.No. 3,620,140.

[52] U.S.Cl. Q. ..95/4.5 [51] Int.CI. ..B4lb 21/22 [58] Field of Search.'.95/4.5

[56] References Cited UNITED STATES PATENTS 2,787,654 4/1957 Peery.....l78/2 CHARACTER PRESENTATION PLANE CHARACTER SPACING MECHANISM TOFONT ILLUMINATION CONTROL GENERAL CONTROL CIRCUIT [is] 3,695,156 [451'Oct. 3, 1972 Primary Examiner-John M. Horan Attorney-William D. ORcilly[57] ABSTRACT spacing mechanism thereof.

7 cam, 11 Drawing Figures LENS SYSTEM FILM PLACE drn CHARACTER AND SPACEWIDTH VALUES PATENTEDMIB m2 3.695156 SHEET 1 0F 4 LENS SYSTEM CHARACTERPRESENTATION PLANE F2 CHARACTER SPACING MECHANISM CHARACTER AND SPACEWIDTH VALUES To FONT FONT SELECTION CORRECTION CONTROL FIG. I

- GENERAL CONTROL CIRCUIT DIRECTION OFL'NESPAC'NG Photon, Inc.Wz'lmirglon, Mass. DISPLACEMENT CHARACTER SPACING T I," DISPLACEMENT .1.HI

2dm dm "5 7 '5 i b K b ,Jc;: Z E d d d FLAHL'NE INVENTOR 2 e 6 e 22LOUIS M.MOYROUD ATTORNEY.

CORRECT.

FONT SHIFT CONTROL I98 SPACING r CARRIAGE CONTROL SHUTTER STEPPER FACESHIFT SELECT.

PAIENTEIIBIITII I972 FIG. 7

D U 2 w L I m1 Rm. 8 mm 0M w T. N .EM, s W U .0 L I 8 w 0 29 m Hm F s TT. mm 2 9 x v O 9 8 M. Z 4 w I 9. v QM 4 2:. E: 2: 9 HWII o ZU 8 0 [I III I 7 F 1 u U LMU 4 3 I TIMING PULSES TO SPACING CARR.CONTROL 1PHOTOCOMPOSING MACHINE BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTIONThe present invention pertains to a unique approach for shifting fromone style or font of characters to another in many differentphotocomposing machines. The present application is acontinuation-in-part of U.S. application Ser. Nos. 827,128filed May 21,1969 now U.S. Pat. No. 3,643,559,690,720 filed Dec. 13, 1967 now U.S.Pat. No. 3,590,705, and 843,297 filed July 22, 1969 nowU.S. Pat. No.3,620,140. The disclosures of each of the afore-mentioned applicationsarev hereby incorporated by reference in the present application.

The basic functions of a photographic composing machine are selectionand presentation of characters at a pre-determined location, projectionof a character image through a' lens, positioning of the image at the.correct location in a line of composition onanimagereceiving surfacesuch as afilm, and'vertical spacing of composed lines from one anotheron the film. Other important functions are selection of a desired fontof characters from among several groups, selection of a character imagesize by changing optical magnification (by the use of a lens turret,zoom lens, etc.), and line justification (including quadding, leadering,and tabulation).

In the present invention the basic character spacing mechanism utilizedto space characters alongaline (or the line-spacing mechanism to spacelines on apage), is utilized to replace the conventional method ofdisplacement of a font of characters in order'to obtain a preselectedprojection position.

In most photographic type composing machines, selected characters aremade to appear at a character presentation point." Various means areutilized to achieve this result, but the most widely used means'involvea continuously rotating matrix (either a disc or drum) associated with aflash device. A matrix usually contains several rows or circlesofcharacters; generally each row represents a difi'erent font. In theprior art a relative mechanical displacement of the matrix was necessaryto move a desired font into operative position for characterpresentation at a common projection point. In all cases, this approachinvolves specialfont' shifting mechanisms which are utilized tomechanically or optically move a selected group of characters (or theirimage path) to a pre-determined'positipn ona common optical axis. In theprior art there is always a special mechanism introduced in amultiple-font machine for the sole purpose of bringing the selected fontto a given point or onto a given path, which in cludes mechanical ormechanical-optical means.

On the other hand, in the present invention'we are dealing with aphotographic type composing machine in which different fonts can appearat different character-presentation points or paths. These points are sopositioned that the existing character spacing mechanisms of the machinecan be utilized to compensate for the fact that the characterpresentation points are distinct and would produce character images atundesired locations on the photosensitive surface, but for thecompensation capability of the invention. Thus, the character spacingmechanism is instructed by the font shift mechanism to add to orsubtract from its normal characterspacing function. Also, selectiveillumination means are provided for the different-fonts associated withdifferent character presentation points or paths, for example, as isshown in U.S. Ser. No. 690,720 filed Dec. 13, l967.

Thus, one advantage of the invention is the eliminationof specialmechanisms such as disclosed in the prior art for the purpose ofreplacing a font by another font at a character presentation point. Asecond advantage afforded by the invention is the increased machinespeed resulting from. a saving of the time required forv theoperation-of the special mechanism, which is usuallyquite substantialbecause of the inertia of moving parts:involved (which) createvibrations or bounce), and the high accuracy that. must be achieved. 2

The present inventionwill be. more fully described in the detaileddescription which follows, in which:

FIG. 1 is aschematic view of the basic elements of a photocomposingmachine, .with the addition of multiple fonts capability;

FIG. 2 represents a partial'section of a multi-font matrix;

FIG. 3 is an example'of a line of text comprising three different fonts;

FIG. 4 is a schematic representationof an embodiment of the inventionwith a rotating matrix that is also translated to achieve characterspacing;

FIG. 5 is another representation of the embodiment of FIG. 4 withtheaddition of point-size selection capability;

FIG. 6 is an embodiment of the invention similar to the oneshown in FIG.4 except thatthe character spacing mechanism includes a translatinglens;

FIG. 7 is a'schematic representationof another embodiment of theinvention in which the matrix is represented by a multi-fonts drum andthe spacing mechanism by a translating lens;

FIG. 8' is a cross-section of an embodiment using the drum of FIG. 7butwith aplurality of flash lamps as illuminating means rather than ashutter band;

FIG. 9 is a schematic representation of another embodimentof theinvention in whichthe relative motion between matrix and film isobtained. by reflecting surfaces positioned between the matrixand theprojection lens to avoid spacing corrections caused by differentmagnification ratios;

FIG. 10 represents the portion of amulti-fonts matrix continuouslymoving in a character spacing direction; and

FIG. 11 represents schematically the use of vertical character spacing(interline spacing or leading) for font selection.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a block diagram showingthe basic components of a photographic type composing machine. Theselected character is presented at a point such as F2 in a characterpresentation plane 1. F2 could be the location of a reference point of acharacter (as defined in co-pending U.S. application Ser. No. 827,128filed May 21, 1969) at the time the character is illuminated forprojection. If desired, limiting apertures or windows such as can be cutout of a mask to limit the illumination to the selected character at theexclusion of the others. Each selected character of a line belonging tothe same row of characters (in the case of a rotating disc or drum) orto the same matrix plate appear successively at point F2 from which theyare projected by optical system 4 to film 2. The characters are properlyspaced along the base line BL by the relative translation of one (ortwo) of the three major components of the machine i.e., characterpresentation plane 1, lens 4, and film 2). For example, such spacing canbe obtained by moving the character presentation point by distancescorresponding to the width of each character of the matrix to beprojected (and independently of the optical magnification) as explainedin copending application U.S. Ser. No. 690,720 filed Dec. 13, 1967, orcharacter spacing can be achieved by moving the projection lens 4, or bymoving the film 2 in a direction parallel to the base-line BL of theline being composed. In these two latter cases, the displacement of thelens or the film will depend on the width of the matrix character and onthe magnification ratio of the optical system. Of course, it is possibleto achieve relative displacements of one of the three basic componentsrelative to the others by other means, such as is explained in U.S. Pat.No. 2,670,665, or co-pending U.S. application Ser. No. 843,297 filedJuly 22, 1969.

The invention will now be described as it can be applied to machineshaving a character matrix in the form of a band, disc or drum providedwith several rows of characters of different fonts. FIG. 2 shows aportion of a matrix strip 14 provided with three rows of characters 44,46, and 48. In this example the matrix strip is mounted on acontinuously rotating drum so that the displacement of characters occursvertically, as shown by the arrows in the figure. Selected charactersare projected to the light-sensitive surface as they cross the flashline FL. Each row can be selectively illuminated either by moving awindow (as explained in co-pending U.S. application Ser. No. 790,620),or by moving a flash lamp or light pipe from row to row, or by usingindividual flash lamps for each row, as shown at 18, and 22. Thecharacter presentation locations corresponding to the three rows of FIG.2 are shown at F1, F2 and F3 in FIG. 1. It can be seen in FIG. 1 thateach row is associated with a distinct optical projection path 132, 133and 134 respectively, spaced from each other by a distance d. Afterpassage through the optical system 4, the spacing of projected characterimages belonging to different rows along base-line BL on film 2 is equalto the distance between rows on the matrix multiplied by the opticalmagnification, as represented by dm in FIG. 1.

' In order to correctly space in the same line of text, characters orwords belonging to different fonts, or to keep even margins for lines ofdifferent fonts, it is necessary to introduce a correction orcompensation that will activate the spacing mechanism to cause the imageon the film to be moved forward or backward in relation to the directionof composition a distance dm. The correction can be combined with thespacing of the previous or succeeding character (or word space). In thiscase the character spacing mechanism 8 includes an adder giving anoutput equal to the algebraical sum of the character width (previouslyflashed or to be flashed), the width of the word space (in most cases)and the correction d or dm, all these values being expressed in commonwidth units. Box 12, which represents the character spacing control, mayinclude width tables" or width cards" such as described in U.S. Pat. No.3,332,617 and a justifier and, in some cases, a multiplier such asdescribed in U.S. Pat. No. 2,876,687. Box 10 can contain storedinformation necessary to produce a font shift" at the command of acontrol code to cause the selective illumination of F 1, F2 or F3, andalso to introduce the necessary font shift spacing correction into thecharacter spacing control. Box 9 represents the general control circuitof the machine.

The line of FIG. 3 comprising words of three different fonts illustrateswhat is meant by character spacing displacement" and line spacingdisplacement. This figure also illustrates what would happen if nospacing correction is made following a font shift. In the absence of aspacing correction, the second word Inc. would be moved to the left by adistance 2 dm from its desired position, and the third word Wilmingtonby a distance dm to the right, from their respective proper positions.(The first letter of these words is shown in dotted lines and at anotherlevel for better clarity. Also, in the drawings the reversing action ofthe optics is ignored for the sake of clarity).

In systems utilizing the optical leverage principle I (in whichcharacters are spaced before they are sized) such as shown in FIGS. 4,5, and 9 of the drawings, the font shift correction is, in absolutevalue terms, equal to the distance (in width units) separating the fontrows, and is totally independent of the magnification ratio. Forexample, in FIG. 1, the spacing mechanism will introduce a correction din one direction for a shift from font 44 (FIG. 2) to font 46, acorrection 2d in the same direction for a shift from font 44 to font 48,a correction d in the other direction for a shift from font 48 to font46, etc.

The basic character presentation and spacing system described inco-pending application Ser. No. 690,720 is illustrated in FIG. 4. Inthis figure, the matrix disc 6 is continuously rotatable for characterselection and presentation purposes, and is also adapted to be movedalong lines y y to obtain proper character and word spacing. Three fontrows are shown at 17. Characters are projected through a fixed lens 4 tofilm 2 and are aligned along baseline BL to form a line of composition.Font shift correction or compensation is obtained by moving matrix disc6 along y y by a distance equal to the spacing of consecutive rows. Forexample, passage from character presentation point F 1 (bold characters,as shown in FIG. 2) to F3 (roman characters) is achieved by moving thedisc to the right (as represented in FIG. 4) by a distance 2d in orderto bring the projection F3 of point F3 to the location on the film whichwas receiving the projection F1 of point F1 before correction. In thisparticular case the correction is negative, since it goes against thenormal character spacing displacement of disc 6 as represented by arrow69.

The projection system shown in FIG. 5 is the same as the one of FIG. 4except for the addition of one lens to obtain different character sizeson the film. Two lenses of different focal length are shown at 40 and42. Of course there would be only one lens in the optical path at atime, with selection of one lens or another being generally obtained bythe rotation of a lens turret or other analogous size-changingmechanism. It can be seen in FIG. 5 that a displacement d of matrix disc6 will move the projection point on the filmby a distance 58 whenrelatively large magnification lens 40 is used, and by a smallerdistance 62 when relatively small magnification lens 42 is used. Becauseof optical leverage(spa'ce before you size), the distances 58 and 62 arein the same ratio as themagnified images, so that character spacingcorrection is automatically obtained and the magnification ratio doesnot have to be taken into account when the matrix is're-positioned bythe character spacing mechanism in order tocompensate for a shift fromone font to another.

Another embodiment of the invention in a system using optical leverageis shown in FIG. 9. Here the continuously rotating matrix 6 is a discprovided with several circles (rows) of characters of different fontssuch as shown at 118, 121 and 122. Illumination of row 118 is obtainedby a flash unit 136 comprising, for example, a flash lamp, a condenser,and a light pipe 18. Selective illumination can be obtained by movinglight. pipe 18 opposite the selected font or, preferably, by associatinga separate flash unit with pipe 20 to illuminate font 121, and anotherpipe 22 to illuminate font 122 and so forth. The projection system, asdescribed in copending US. application Ser. No. 843,297 includes areflecting roof composed of reflecting surfaces 124 and 126 (such as aprism or mirror pair) that is moved in a direction parallel to thematrix and the flash line FL intersecting the different characterpresentation points (see FIG. 1) for character spacing purposes. Acharacter-bearing bundle of light 138 emerging from the reflecting roofenters a projection lens 40 (one of several interchangeable lensesproviding different magnifications as, for example, in a lens turret)and forms an image of the selected character of the selected size onfilm 2. As shown in FIG. 9, in this particular embodiment of theinvention, passage from one font to another is obtained byre-positioning or correcting the reflecting roof along its normalcharacter-spacing path by a distance equal to one-half the distanceseparating the font that was used from the font to be selected. Thisreduced displacement is caused by the double reflection of the roof asexplained in co-pending application Ser. No. 843,297.

Thus, in the example of FIG. 9, passage from font 118 to font 122 willbe obtained by moving the roof by a distance S8 to bring the firstreflecting surface from position 124 to position 124b, and the secondreflecting surface from position 126 to position 126b. Of course, asthis operation takes place the source of illumination is transferredfrom pipe 18 to pipe 22, for example by energizing the flash lampassociated with pipe 22. The character-bearing bundle emerging from 118is shown at 135. The bundle emerging from 122 is shown at 137. Thesebundles will follow the same path 138 at the exit of the roof becausethe virtual image of a character located at point 118 (produced by thetwo mirror surfaces at positions 124 and 126) is located at the samepoint as the virtual image of a character located at point 122 (producedby the same reflecting surfaces after they have moved to positions 124b126b). The location of the virtual images is shown at 120. Point 120 issymmetrical with point (or character position) 1 18 in relation to roofapex 140 whenthe mirrors are as shown in solid lines, and is alsosymmetrical to point 122 after the apex has moved from position 140 toposition 14%. The virtual images of points 1 18 and 122 produced by thefirst reflecting surface are shown at 1 19 and 123 respectively.

Thus'far, the inventionhas been described as it can be .incorporatedinto machines utilizing the optical leverage principle, which is notpresent in FIG. 6 of the drawings. In FIG. 6, matrix disc 6 is rotatingaround a fixed axis 39 and character presentation points 44 and 48 areat fixed locations. The character spacing function is accomplished bydisplacing the projection lens (such as 40) along a line 66 parallel tofilm 2. Another lens 42 producing a relatively smaller magnificationthan lens 40 can be used to produce smaller images, said lens beingmoved along path 64. As can be seen in the figure, in order to introducethe font shift correction to compensate for the passage from font 48 to.44, the lens carriage will have to be moved by a distance if lens 42 isbeing used and by a distance 73 if lens 40 is being used, so that ineither case the image on the film will be moved from point 70 (image offont 48) to point 72 (image of font 44). Therefore, the characterspacing mechanism will be re-positioned (or corrected) following a fontshift command by a value which depends upon the spacing of the font rowson the matrix, and upon the magnification ratio. These corrective valuescan be pre-computed and stored, and can be retrieved whenever necessaryat the command of a font shift control code.

In the arrangement of FIG. 7 the character spacing function is alsoobtained by translating a lens 76 along path 77 by variable amountsdepending upon two factors: the width of the master character on thematrix, and the magnification ratio. A continuously rotating drum isprovided with eight matrix strips 92-1 to 92-8. Each strip can containone or more fonts. The flash timing is obtained as explained in US. Pat.No. 2,790,362 by a band of transparent slits 80. A flash lamp (notshown) is located inside the drum, but only the light emerging from theselected matrix band can reach the optical system. This is achieved bythe use of a shutter band 82 provided with an aperture or window 88 thatcan be moved along a direction parallel to the axis of the drum, and islocated opposite the selected font. Band 82 could be made of any thinflexible material impervious to light. Band 82 is kept under tension bythe use of spring-loaded drums 84 and 86 secured to the frame 102 of thematrix drum. Band 82 can be moved longitudinally by a stepping motorcontrolled by the font shift mechanism 106, which also controls thedisplacement of lens 76 (as shown) to correct or re-position the lenseach time a different font is selected.

For example, lens 76 is shown in solid lines at the position it occupiesat the beginning of a line of length LL to be flashed onto film 2. Asshown, the first character of the line will be projected from location88 on the matrix to location on the film. If it is desired to shift fromfont 92-1 to font 92-8 at the beginning of "fonts on the matrix as wellas the magnification ratio.

The different correction values, as in the example of FIG. 6, can bepre-computed and stored in a memory as explained above. These values,which could be stored in box 106, are transferred to the carriagespacing control by the appropriate font shift signals emerging from thegeneral control circuit of the machine represented by box 1 12. Ofcourse, the position of lens 76 along line 77 can be corrected at anytime during the composition of a line, either before or after a fontshift command.

As mentioned above, the lens positioning correction could beincorporated into the lens displacement required to space normally thelast read character (or interword space) from the adjacent character.The extreme positions of the projecting and spacing lenses (in the caseof the magnification shown) are shown at 76 (font 92-1) and 76-3 (font928). In FIG. 7 this projection lens is located at an equal distancefrom the matrix and the film for a one-to-one magnification ratio. Inthis case, the total maximum travel of the lens will be equal toone-half the maximum length of line LL, plus one-half thedistancebetween the most widely spaced font strips. Of course, it ispossible to replace a lens by another lens having a differentmagnification. In this case, in order to preserve the same left handmargin on the film, a supplemental lens positioning correction MC(depending only on the magnification ratio) must be introduced. Thiscould be accomplished by again storing the margin correction values in astorage such as 105 activated at the end of each line by circuit 1 12.

FIG. 8 represents a system similar to the one shown in FIG. 7 except forthe replacement of shutter band 82 of FIG. 7 by a multiplicity of flashunits 92-1 to 92-8, each one associated with a matrix strip 94-1 to 94-8respectively, and separated by light baffles 100. A font shift signalcauses the energization of the flash unit associated with the desiredfont strip through a flash selection circuit 116 controlled by the fontshift circuit 1 l4.

In all of the embodiments described above the character presentationpoints such as F 1, F2, and F3 of FIG. 1 are located on a line parallelto the base of the line being composed, so that passage from onepresentation point to another is accomplished by appropriately adjustingthe character spacing mechanism utilized to space characters along aline. In another embodiment of the invention shown in FIG. 11, thepreviously indispensable font shift mechanism of the prior art iseliminated by using the line-spacing or leading mechanism of the machineto adjust for a font shift (see also FIG. 3). Such a system is alsodisclosed in application Ser. No. 827,128. The character matrix drum 28is provided with matrix bands 141, 142, 143 and 144 representingdifferent fonts of type. As shown in FIG. 10, the characters of thematrix are moving in a direction parallel to their base line (inopposition to the systems previously described in which the matrixcharacters move in a direction perpendicular to their base line, forexample, as illustrated in FIG. 2). The

selected characters are projected by a flash lamp 24, 25, 26 or 27 ontoa film 2 through a lens 4. The normal function of leading mechanism 32is to move the film at the completion of each line for line spacingpurposes. In the present invention, this same mechanism is also used toposition, on the same base line, characters projected from any of thefour font rows of drum 28. It is apparent in FIG. 11 that, withoutcorrection, characters of rows 141, 142, 143 and 144 would be projectedat 145, 146, 147 and 148 respectively. The correction for font shift isaccomplished by moving the film up or down, that is, from the supplyspool 34 to the take-up spool 36 or vice versa, depending on the fontbeing used and the new font selected (as inthe example describedrelative to FIGS. 4, 7 and 8 above). In this particular embodiment, theamount of film displace ment correction depends on the spacing d betweenrows of different fonts and the magnification ratio i.e., no opticalleverage in this embodiment).

The system represented in FIG. 11 is particularly ad vantageous in acertain type of high speed machine such as described in Ser. No.827,128, but it does not permit rapid font shift during the compositionof a line, as is the case in systems in which the character spacingmechanism (rather than line spacing mechanism) is utilized as the fontchanging means.

While a rotating matrix has been described, it should be understood thatan indexing or start-stop matrix can also be used in the presentinvention. Also, it is evident that more than one disc or drum may beutilized, if desired.

The foregoing description is intended to be illustrative only. Variouschanges or modifications in the disclosed embodiments may occur to thoseskilled in the art. It is understood, therefore, that all suchmodifications as would be apparent to one skilled in the art areincluded within the scope of the present invention.

What is claimed is:

1. A photocomposing machine comprising:

a character presentation area having a plurality of character arrays,said area including at least one character projection zone for each ofsaid arrays, said character projection zones being spaced from oneanother within said character presentation area,

means for moving the character arrays through their respective characterprojection zones,

means for illuminating selected characters of an array within arespective projection zone,

a surface for receiving character images,

means for projecting the images of selected characters from saidprojection zone to said imagereceiving surface in order to form a lineof composition thereon,

means for spacing said character images along a common base line of saidsurface in accordance with their respective widths, thereby forming aline of composition thereon, said character spacing means havingassociated therewith a control circuit for controlling the movement ofsaid spacing means, said control circuit further being adapted tocompensate for the fact that a change from one array to another resultsin a shift from one of said character projection zones to another spacedtherefrom by adjusting the position of said character spacing means inresponse to said array change, and v means for spacing said composedlines from one another on said surface.

2. The machine of claim 1 in which said character spacing meanscompensates for said array change by moving the character images apredetermined amount along a path parallel to said common base line.

3. The machine of claim 1 in which said character presentation areacomprises a rotatable character-carrier, and the character arrays movethrough their respective character projection zones such that thecharacters of said arrays move through said zones in a directionperpendicular to their base lines.

4. The machine of claim 1 including a size-changing mechanism forvarying the size or magnification ratio of the character images whichare projected onto said image-receiving surface, said size-changingmechanism being positioned in the optical path between said characterspacing means and said image-receiving surface such that when a changefrom one array to another is made, the character spacing meanscompensates therefor by taking into account only the distance by whichthe character projection zone presently in use is spaced from the zonepreviously in use, said compensation or correction being accomplishedindependently of the magnification ratio of said size-changingmechanism.

5. The machine of claim 1 including a size-changing mechanism forvarying the size or magnification ratio of the character images whichare projected onto said image-receiving surface, such that when a changefrom one array to another is made, said character spacing meanscompensates therefor by taking into account the distance by which thecharacter projection zone in use after the array change is spaced fromthe zone in use means for projecting the images of selected charactersfrom said projection zone to said imagereceiving surface in order toform a line of composition thereon,

means for spacing said character images along a common base line of saidsurface in accordance with their respective widths, thereby forming aline of composition thereon, and

means for spacing said composed lines from one another on said surface,said line spacing means having associated therewith a control circuitfor controlling the movement of said spacing means, said control circuitfurther being adapted to compensate for the fact that a change from onearray to] another results in a shift from one of said 0 aracterprojection zones to another spaced therefrom by adjusting the positionof said line spacing means in response to said array change.

7. The machine of claim 6 in which said line spacing means compensatesfor said array change by moving the character images a predeterminedamount in a plane perpendicular to said common base-line.

1. A photocomposing machine comprising: a character presentation areahaving a plurality of character arrays, said area including at least onecharacter projection zone for each of said arrays, said characterprojection zones being spaced from one another within said characterpresentation area, means for moving the character arrays through theirrespective character projection zones, means for illuminating selectedcharacters of an array within a respective projection zone, a surfacefor receiving character images, means for projecting the images ofselected characters from said projection zone to said image-receivingsurface in order to form a line of composition thereon, means forspacing said character images along a common base line of said surfacein accordance with their respEctive widths, thereby forming a line ofcomposition thereon, said character spacing means having associatedtherewith a control circuit for controlling the movement of said spacingmeans, said control circuit further being adapted to compensate for thefact that a change from one array to another results in a shift from oneof said character projection zones to another spaced therefrom byadjusting the position of said character spacing means in response tosaid array change, and means for spacing said composed lines from oneanother on said surface.
 2. The machine of claim 1 in which saidcharacter spacing means compensates for said array change by moving thecharacter images a predetermined amount along a path parallel to saidcommon base line.
 3. The machine of claim 1 in which said characterpresentation area comprises a rotatable character-carrier, and thecharacter arrays move through their respective character projectionzones such that the characters of said arrays move through said zones ina direction perpendicular to their base lines.
 4. The machine of claim 1including a size-changing mechanism for varying the size ormagnification ratio of the character images which are projected ontosaid image-receiving surface, said size-changing mechanism beingpositioned in the optical path between said character spacing means andsaid image-receiving surface such that when a change from one array toanother is made, the character spacing means compensates therefor bytaking into account only the distance by which the character projectionzone presently in use is spaced from the zone previously in use, saidcompensation or correction being accomplished independently of themagnification ratio of said size-changing mechanism.
 5. The machine ofclaim 1 including a size-changing mechanism for varying the size ormagnification ratio of the character images which are projected ontosaid image-receiving surface, such that when a change from one array toanother is made, said character spacing means compensates therefor bytaking into account the distance by which the character projection zonein use after the array change is spaced from the zone in use before thechange, and by taking into account the magnification ratio of saidsize-changing mechanism.
 6. A photocomposing machine comprising: acharacter presentation area having a plurality of character arrays, saidarea including at least one character projection zone for each of saidarrays, said character projection zones being spaced from one anotherwithin said character presentation area, means for moving the characterarrays through their respective character projection zones, means forilluminating selected characters of an array within a respectiveprojection zone, a surface for receiving character images, means forprojecting the images of selected characters from said projection zoneto said image-receiving surface in order to form a line of compositionthereon, means for spacing said character images along a common baseline of said surface in accordance with their respective widths, therebyforming a line of composition thereon, and means for spacing saidcomposed lines from one another on said surface, said line spacing meanshaving associated therewith a control circuit for controlling themovement of said spacing means, said control circuit further beingadapted to compensate for the fact that a change from one array toanother results in a shift from one of said character projection zonesto another spaced therefrom by adjusting the position of said linespacing means in response to said array change.
 7. The machine of claim6 in which said line spacing means compensates for said array change bymoving the character images a predetermined amount in a planeperpendicular to said common base-line.